A case for high performance By Joe Mellott Selecting products and services can be a difficult proposition. This couldn’t be truer than when selecting your new roof solution. Currently, there are hundreds of possible solutions, from traditional long-standing products, like built-up asphalt roofing, to novel newmarket solutions such as TPOs and vegetative roofing. Making the best decision could be the difference between long-term success and short-term failure. Roof installation is an expensive proposition and customers need to balance initial cost versus life cycle cost; performance versus economics.
High-Performance roofing provides long-term solutions.
When selecting your new roof, it’s important to consider a number of factors including: • Environmental conditions of the roof, extreme weather conditions, excessive precipitation, chemical exposure or roof top. • Desired service life of the system. • Energy expectations of the solution as a contributing factor to energy savings. It is important to have detailed discussions with manufacturers and installers while making these decisions. The correct decision could mean 30 years of successful performance. The two most critical factors involved in roof material design are: • Tensile strength. ARCHITECTURE & LANDSCAPE ARCHITECTURE
Over 90 years of collective experience in the planning, design and construction of school facilities in British Columbia.
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Ops Talk • Spring 2012
9355 Young Road Chilliwack, BC V2P 4S3 Tel: 604|793|9445 Fax: 604|793|9446 chp@chparchitects.com www.chparchitects.com
• Elasticity (rubber modification). Roofs can begin to fail from man-made and natural occurrences such as dropped equipment, the impact of hail and extreme foot Roofing systems have additional environmental and application demands.
traffic. The use of high-strength tensile reinforcement helps roofs to resist damage caused by these natural occurrences. Tensile and tear-strength properties are two of the most important factors in determining roof life expectancy. Roof tops expand and contract due to roof top temperature changes from day to night, summer to winter and during rain and snow. These movements can be well managed through the use of rubber-modified compounds (specifically SBS modified bitumen in the case of modified bitumen membranes). The sheets are welded together with heat, adhesives or hot asphalt. The roof becomes a continuous waterproofing layer of the modified compound. The more flexible the compound, the more thermal movement it can handle. A good way to determine the level of rubber modification is to examine the low temperature flexibility (LTF) of the membrane. The higher the rubber content, the lower the passing LTF. Below the LTF
